This application relates to a gas turbine engine having multiple bypass stream flows and wherein heat exchangers are staged within the bypass flows.
Gas turbine engines are known and include a fan delivering air into a bypass duct as propulsion air and, further, into a core engine. The core engine flow passes to a compressor where it is compressed and it is then delivered to a combustion section where it is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors driving them to rotate.
Modern engines rely on the bypass flow to provide a larger and larger percent of the propulsion for the aircraft.
In some applications and, in particular, high speed military applications, there has recently been development of a multiple bypass flow engine. In such engines, there is more than one bypass duct to provide propulsion for the aircraft.
The bypass ducts are also utilized to cool heat exchangers for various functions. The bypass ducts in military applications generally are not unduly large and, thus, there is limited “face” area for air to pass through the heat exchangers.